In the manufacture of printed circuit boards, printed circuit elements and like goods, and in processes in connection with the same, it has become commonplace to deliver the articles, such as printed circuit boards, through a chamber in a continuous manner, while the articles are being treated by the spray of a suitable treatment fluid, such as an etchant onto them. Generally, the etchant is of a corrosive nature, such as ammonium hydroxide and ammonium chloride, with a suitable chelating or complexing agent, although other etchants or treatment fluids may also be utilized. See, for example, U.S. Pat. No. 4,233,106, the disclosure of which is herein incorporated by reference.
Most particularly, when the treatment fluids are corrosive in nature, and are dangerous to personnel handling the apparatus, particularly to the skin, eyes, etc., of such personnel, and particularly to nearby equipment as well, it is desirable to prevent access by such personnel to such treatment fluid.
In the course of preventing such access, it has been known to perform the various treatments in chambers, with limited, slit-like access at the inlets and outlets thereof to the treatment chambers. See, for example, U.S. Pat. Nos. 3,776,800 and 4,015,706, the entire disclosures of which are herein incorporated by reference.
In many such operations, it is desirable to provide access to the interior of the chamber by personnel, which access may readily be obtainable upon opening or removing a door or the like, for purposes of repair, cleaning, correcting some malfunction, or for any myriad of reasons that may dictate the desirability of access to the interior of the chamber.